A bomb attack by Kurdish militants has killed a police officer in southeast Turkey and another device was defused outside a local government building.

Turkey has been on high alert since a suicide bombing, claimed by a Kurdish militant group, killed 37 people in the capital Ankara on Sunday.

Germany shut down its diplomatic missions and schools in Turkey, while the U.S. and other European embassies warned citizens to be vigilant.

Kurdistan Workers Party (PKK) militants were believed to have staged Friday's attack on the armoured police vehicle during security operations in the town of Nusaybin, near the Syrian border, security sources said.

Police forensic officials work at site of a suicide bomb in Ankara, Turkey (AP)

In the town of Hani, also in the mainly Kurdish southeast, police found a vehicle loaded with 150 kg (330 lb) of explosives which they believed was to be detonated during events to mark the anniversary of a World War One battlefield victory at Canakkale on Friday, state authorities said.

"Thanks to the alertness of security forces, there was no loss of life or damage. Efforts to ensure peace and security for our people will continue decisively and uninterrupted," the provincial governor's office said.

The Spanish and Italian embassies urged their citizens to avoid busy locations, celebrations and rallies on Sunday and Monday, when Kurds celebrate the Newroz New Year festival.

At the height of the PKK insurgency in the 1990s, the festival was often marked by violent clashes between Kurdish protesters and the security forces. It coincides with the spring thaw, a time when in previous years PKK fighters re-entered Turkey from mountain hideouts in northern Iraq.

NATO member Turkey also faces a threat from Islamic State militants, blamed for several attacks including a suicide bombing in Istanbul in January that killed 10 German tourists.

With conflicts in the region driving migrants towards Europe, Prime Minister Ahmet Davutoglu and EU leaders tried to clinch a deal in Brussels on Friday to help stop the flow via Turkey.

At least 37 people were killed in the bombing in Turkey

Germany said it was keeping its diplomatic missions and schools closed until the weekend due to a highly credible security threat. Der Spiegel magazine reported that U.S. and Turkish intelligence, as well as Kurdish security sources, had warned Berlin of a planned suicide attack, linked to Islamic State, on German diplomatic missions or schools.

"DANCING IN A MINEFIELD"

A PKK ceasefire collapsed in July, triggering daily violence which has killed more than 1,000 militants, security force members and civilians.

In the latest clashes, 10 PKK militants were killed in fighting in the southeastern towns of Yuksekova, Sirnak and Nusaybin on Thursday, the Turkish military said.

European leaders have expressed concern about the loss of civilian life in military operations and have urged Turkey to use proportional force.

President Tayyip Erdogan retorted: "Our struggle against terrorism is measured and legitimate ... Every terrorist organisation active in our region and in Turkey has unified against Turkey.

"Many states, primarily Western countries, still cannot display a principled stance against these groups," he added in a speech on Friday.

"Europe's continued reckless behaviour is like dancing in a minefield ... I am telling nations that directly or indirectly embrace terrorist groups: you are nursing a viper in your bosom," he said at Canakkale commemorations.

The Istanbul governor's office has dismissed the German closures, accusing Berlin of taking action on the basis of "unconfirmed rumours" without consulting Turkish authorities.

Under the headline "The merchants of fear are at it", the pro-government Sabah newspaper said Germany was trying to stoke unrest and that a investigation had been opened into the German High School in Istanbul for closing without consulting the education ministry.